Immunophenotyping Of Helicobacter Pylori And HLA-DQA1 Allele Frequencies In The Families Of Children With Chronic Gastritis

AIM:To investigate the prevalence of Helicobacter pylori(Hp) infection and the strains of Helicobacter pylori in families of children with chronic gastritis.To explore human leukocyte antigen DQA1 allele frequencies in the families of children with chronic gastritis infected by Hp.To investigate the relationship between clinical outcome and human leukocyte antigen DQAl alleles after Hp infection,so that we can find if there are some associated genes affected Hp infection.METHODS:The immunophenotyping of Hp is determined by Western blot (immunoblot) technique and the serum antibody of Hp is tested by dot immunogold filtration assay in 70 members among 13 families.There are 68 members with Hp infection among 13 families.PCR-SSP technique is applied to identify HLA-DQAl allelic distribution between 38 members with gastrointestinal symptoms and 30 members without gastrointestinal symptoms.RESULT:The total seropositive rate and the immunophenotyping of Hp antibodies in 70 members are 100%and 97.1%respectively.The prevalence of Hp typeⅠis 62.8%.The prevalence of Hp typeⅡis 34.3%.There is significant difference between children and elders group about Hp strains rate(P＜0.05).There also is a significantly difference between the members with(57.8%) and without(34.4%) gastrointestinal disease about the positive rate of VacA strains(P＜0.05).There is familial cluster phenomenon in family members suffering from gastrointestinal diseases with Hp infection.HLA-DQAl~*0302 allelic frequency is significantly higher in the members with gastrointestinal symptoms than in the members without gastrointestinal symptoms(18%vs 0,χ~2= 0,P =0.001,P_c＜O.05,OR=18.776).HLA- DQAl~*0105 allelic frequency is higher in the members with gastrointestinal symptoms than in the members without gastrointestinal symptoms (7%vs 0,χ~2= 0,P = 0.049),but the signification disappeared when the allelic Bonferroni correction for comparisons were applied as required(P_c＞0.05).CONCLUSION:The seropositive rate of Hp antibodiies is high in families of children with chronic gastritis.Hp strains are associated with age.The seropositive rate of VacA is associated with gastrointestinal symptoms.There are HLA-DQAl~*0302 allelic frequency difference between the members with and without gastrointestinal symptoms.HLA-DQAl~*0302 may be an associated gene contributed to Hp infection.However,HLA-DQAl~*0105 allele should be studied further.